The Camera tag contains four groups which are used to control those parts of the Maxwell camera which have no matching parameter in C4D. The Camera tag may be attached either to a C4D camera, or to the Scene you are working with.
Exposure
EV
EV, or Exposure Value is a number used to express the basic exposure which will be seen in the exported MXS. EV may be used to set the exposure directly, where brighter scenes will require a higher EV, or it may be used as an exposure readout when setting fStop, Shutter, and ISO manually. For example, an outdoor photo during the daytime may require an EV somewhere around 12-16, while a dark candle-lit scene may require a value much lower, maybe around 4-6. Charts containing recommended EV for various lighting conditions can be found online (see the end of this manual for a chart from wikipedia.org).
EV is not actually a parameter found on Maxwell cameras – it is a theoretical value which is continuously figured by the plugin itself. The 'Lock exposure to EV' option is provided for one basic reason: while exposure may be adjusted manually using different combinations of fStop, Shutter, and ISO, it is possible to adjust the DOF (depth of field) on the camera using the fStop without also affecting the overall exposure of the shot when the plugin is allowed to maintain a given EV. This allows you to adjust the camera's exposure and DOF on a totally independent basis, and this makes setting up exposure much easier and more predictable.
fStop
A camera's fStop refers to the size of its aperture. Lower numbers denote a larger aperture, which exposes the camera's sensor to more light. Additionally, a larger aperture reduces the camera's DOF (i.e. 'depth of field'), or the distance between the nearest and furthest points which will appear in focus. Smaller apertures (higher fStop numbers) result in a greater DOF, but expose the camera's sensor to less light. Therefore, as the fStop is increased, the exposure must be compensated. This can be done manually, by adjusting the camera's shutter or ISO values, or it can be handled automatically by the plugin by enabling the 'Lock exposure to EV' option. When the exposure is locked to the EV, changes to fStop will not affect the overall exposure of the output image, since the plugin will adjust the camera's shutter as necessary to maintain a consistent exposure.
ISO
As with a physical camera, the ISO parameter affects the camera sensor's light-sensitivity. It is not necessary to adjust ISO directly when 'Lock exposure to EV' is enabled.
Shutter
Specified in units of 1/second, this parameter controls how long the camera's Shutter is to remain open. As with the ISO parameter, it is not necessary to adjust the camera's Shutter directly when 'Lock exposure to EV' is enabled. For convenience, the current FPS value is also shown here.
Aperture
The parameters in this section determine the type of lens to use, and also the angle and number of blades used in the camera's aperture, when the Diaphragm type is set to 'Polygonal'. These properties affect the 'bokeh' effect seen in highlights located in out-of-focus portions of the image, which can also be customized using the Custom Bokeh option & parameters.
Rotary Shutter
These parameters express the camera's theoretical rotary shutter angle given a specified frames-per-second rate. The FPS value is always taken from the Frame Rate setting in the current C4D Render Settings.
Z-Clip Planes
When enabled, Maxwell Render will clip any geometry nearer or further than the Near and Far distances defined here. These distances will also be shown in the viewport as red and blue 3D planes when this section is enabled.